Cultivated forms of cucumber belong to the highly polymorphic species Cucumis sativus L. that is grown for its edible fruit. As a crop, cucumbers are grown commercially wherever environmental conditions permit the production of an economically viable yield. They can be hand or mechanically harvested. Cucumbers that are grown for fresh market, also called slicers, are generally hand harvested. Those that are to be processed are called picklers and may be hand or mechanically harvested. They are produced on trailing or climbing vines. On healthy plants there is a canopy of large, regular, three-lobed leaves in an alternate arrangement. Pickling cucumbers grown in the United States have usually blunt and angular fruits. They are white-spined and most possess dark green or medium dark green exterior color. Most slicers have slightly rounded ends and taper slightly from the stem to blossom end, although cylindrical-shaped fruits with blocky or even rounded ends are also available.
Many changes that occurred with the domestication of the cucumber relate to fruit morphology, with a specialization in fruit shape and size. Slicing cucumbers are frequently sold in lengths from 15 cm to 25 cm and diameter varies from 2.5 cm to nearly 7 cm. In the United States, the principal slicer cucumber growing regions are Georgia, Florida, Michigan, California and North Carolina with nearly 42,000 acres out of a U.S. total acreage of 57,500 acres. The main states that produce processing cucumbers are Michigan, North Carolina and Texas. Fresh cucumbers are available in the United States mainly from spring to fall. Cucumbers are consumed in many forms, generally processed for pickling types and as fresh market product for slicers. Although slicing cultivars may be processed, they generally are not acceptable substitutes for the pickling cucumbers.
Cucumis sativus is a member of the family Cucurbitaceae. The Cucurbitaceae is a family of about 90 genera and 700 to 760 species, mostly of the tropics. The family includes melons, pumpkins, squashes, gourds, watermelon, loofah and many weeds. The genus Cucumis, to which the cucumber and several melons belong, includes about 70 species. The cucumber is believed to be native to India or Southern Asia and has been cultivated there for about 3000 years.
Cucumber is distinct from other Cucumis species in that it has seven pairs of chromosomes (2n=2x=14) whereas most others have twelve pairs or multiples of twelve. Pollination techniques for controlled crosses in cucumbers are easy to conduct. If bees and natural pollen vectors can be excluded, the breeder need not be concerned about preventing selfing or other pollen contamination because of the diclinous nature of cucumbers and the stickiness or adherence of pollen to its source flower. There is no wind dissemination of pollen. Pistillate flowers are receptive in the morning or up to midday on the day they open. Cucumbers have a broad range of floral morphologies, from staminate, pistillate to hermaphrodite flowers, yielding several types of sex expression.
Cucumber is an important and valuable field crop. Thus, there is a continued need for new hybrid cucumbers. In particular, there is a need for improved oriental slicer hybrid cucumbers that are stable, high yielding and agronomically sound.